func (api *channellingAPI) HandleSessions(session *channelling.Session, sessions *channelling.DataSessionsRequest) (*channelling.DataSessions, error) {
	switch sessions.Type {
	case "contact":
		if !api.config.WithModule("contacts") {
			return nil, channelling.NewDataError("contacts_not_enabled", "incoming contacts session request with contacts disabled")
		}
		userID, err := api.ContactManager.GetContactID(session, sessions.Token)
		if err != nil {
			return nil, err
		}
		return &channelling.DataSessions{
			Type:     "Sessions",
			Users:    api.SessionManager.GetUserSessions(session, userID),
			Sessions: sessions,
		}, nil
	case "session":
		id, err := session.DecodeAttestation(sessions.Token)
		if err != nil {
			return nil, channelling.NewDataError("bad_attestation", err.Error())
		}
		session, ok := api.Unicaster.GetSession(id)
		if !ok {
			return nil, channelling.NewDataError("no_such_session", "cannot retrieve session")
		}
		return &channelling.DataSessions{
			Type:     "Sessions",
			Users:    []*channelling.DataSession{session.Data()},
			Sessions: sessions,
		}, nil
	default:
		return nil, channelling.NewDataError("bad_request", "unknown sessions request type")
	}
}

func (api *channellingAPI) HandleRoom(session *channelling.Session, room *channelling.DataRoom) (*channelling.DataRoom, error) {
	room, err := api.RoomStatusManager.UpdateRoom(session, room)
	if err == nil {
		session.Broadcast(room)
	}

	return room, err
}

func (api *channellingAPI) HandleAuthentication(session *channelling.Session, st *channelling.SessionToken) (*channelling.DataSelf, error) {
	if err := api.SessionManager.Authenticate(session, st, ""); err != nil {
		log.Println("Authentication failed", err, st.Userid, st.Nonce)
		return nil, err
	}

	log.Println("Authentication success", session.Userid())
	self, err := api.HandleSelf(session)
	if err == nil {
		session.BroadcastStatus()
	}

	return self, err
}

func (api *channellingAPI) HandleConference(session *channelling.Session, conference *channelling.DataConference) {
	if room, ok := api.RoomStatusManager.Get(session.Roomid); ok && room.GetType() == channelling.RoomTypeConference {
		log.Println("Refusing client-side conference update for server-managed conferences.")
		return
	}

	// Check conference maximum size.
	if len(conference.Conference) > maxConferenceSize {
		log.Println("Refusing to create conference above limit.", len(conference.Conference))
		return
	}

	// Send conference update to anyone.
	for _, id := range conference.Conference {
		if id != session.Id {
			session.Unicast(id, conference, nil)
		}
	}
}

func (api *channellingAPI) HandleHello(session *channelling.Session, hello *channelling.DataHello, sender channelling.Sender) (*channelling.DataWelcome, error) {
	// TODO(longsleep): Filter room id and user agent.
	session.Update(&channelling.SessionUpdate{Types: []string{"Ua"}, Ua: hello.Ua})

	// Compatibily for old clients.
	roomName := hello.Name
	if roomName == "" {
		roomName = hello.Id
	}

	room, err := session.JoinRoom(roomName, hello.Type, hello.Credentials, sender)
	if err != nil {
		return nil, err
	}

	return &channelling.DataWelcome{
		Type:  "Welcome",
		Room:  room,
		Users: api.RoomStatusManager.RoomUsers(session),
	}, nil
}

func (api *channellingAPI) HandleChat(session *channelling.Session, chat *channelling.DataChat) {
	// TODO(longsleep): Limit sent chat messages per incoming connection.
	msg := chat.Chat
	to := chat.To

	if !msg.NoEcho {
		session.Unicast(session.Id, chat, nil)
	}
	msg.Time = time.Now().Format(time.RFC3339)
	if to == "" {
		// TODO(longsleep): Check if chat broadcast is allowed.
		if session.Hello {
			api.StatsCounter.CountBroadcastChat()
			session.Broadcast(chat)
		}
	} else {
		if msg.Status != nil {
			if msg.Status.ContactRequest != nil {
				if !api.config.WithModule("contacts") {
					return
				}
				if err := api.ContactManager.ContactrequestHandler(session, to, msg.Status.ContactRequest); err != nil {
					log.Println("Ignoring invalid contact request.", err)
					return
				}
				msg.Status.ContactRequest.Userid = session.Userid()
			}
		} else {
			api.StatsCounter.CountUnicastChat()
		}

		session.Unicast(to, chat, nil)
		if msg.Mid != "" {
			// Send out delivery confirmation status chat message.
			session.Unicast(session.Id, &channelling.DataChat{To: to, Type: "Chat", Chat: &channelling.DataChatMessage{Mid: msg.Mid, Status: &channelling.DataChatStatus{State: "sent"}}}, nil)
		}
	}
}

func (api *channellingAPI) HandleSelf(session *channelling.Session) (*channelling.DataSelf, error) {
	token, err := api.SessionEncoder.EncodeSessionToken(session)
	if err != nil {
		log.Println("Error in OnRegister", err)
		return nil, err
	}

	log.Println("Created new session token", len(token), token)
	self := &channelling.DataSelf{
		Type:       "Self",
		Id:         session.Id,
		Sid:        session.Sid,
		Userid:     session.Userid(),
		Suserid:    api.SessionEncoder.EncodeSessionUserID(session),
		Token:      token,
		Version:    api.config.Version,
		ApiVersion: apiVersion,
		Turn:       api.TurnDataCreator.CreateTurnData(session),
		Stun:       api.config.StunURIs,
	}
	api.BusManager.Trigger(channelling.BusManagerSession, session.Id, session.Userid(), nil, nil)

	return self, nil
}

func (api *channellingAPI) HandleLeave(session *channelling.Session) error {
	session.LeaveRoom()

	return nil
}

func (api *channellingAPI) OnIncoming(sender channelling.Sender, session *channelling.Session, msg *channelling.DataIncoming) (interface{}, error) {
	var pipeline *channelling.Pipeline
	switch msg.Type {
	case "Self":
		return api.HandleSelf(session)
	case "Hello":
		if msg.Hello == nil {
			return nil, channelling.NewDataError("bad_request", "message did not contain Hello")
		}

		return api.HandleHello(session, msg.Hello, sender)
	case "Offer":
		if msg.Offer == nil || msg.Offer.Offer == nil {
			log.Println("Received invalid offer message.", msg)
			break
		}
		if _, ok := msg.Offer.Offer["_token"]; !ok {
			pipeline = api.PipelineManager.GetPipeline(channelling.PipelineNamespaceCall, sender, session, msg.Offer.To)
			// Trigger offer event when offer has no token, so this is
			// not triggered for peerxfer and peerscreenshare offers.
			api.BusManager.Trigger(channelling.BusManagerOffer, session.Id, msg.Offer.To, nil, pipeline)
		}

		session.Unicast(msg.Offer.To, msg.Offer, pipeline)
	case "Candidate":
		if msg.Candidate == nil || msg.Candidate.Candidate == nil {
			log.Println("Received invalid candidate message.", msg)
			break
		}

		pipeline = api.PipelineManager.GetPipeline(channelling.PipelineNamespaceCall, sender, session, msg.Candidate.To)
		session.Unicast(msg.Candidate.To, msg.Candidate, pipeline)
	case "Answer":
		if msg.Answer == nil || msg.Answer.Answer == nil {
			log.Println("Received invalid answer message.", msg)
			break
		}
		if _, ok := msg.Answer.Answer["_token"]; !ok {
			pipeline = api.PipelineManager.GetPipeline(channelling.PipelineNamespaceCall, sender, session, msg.Answer.To)
			// Trigger answer event when answer has no token. so this is
			// not triggered for peerxfer and peerscreenshare answers.
			api.BusManager.Trigger(channelling.BusManagerAnswer, session.Id, msg.Answer.To, nil, pipeline)
		}

		session.Unicast(msg.Answer.To, msg.Answer, pipeline)
	case "Users":
		return api.HandleUsers(session)
	case "Authentication":
		if msg.Authentication == nil || msg.Authentication.Authentication == nil {
			return nil, channelling.NewDataError("bad_request", "message did not contain Authentication")
		}

		return api.HandleAuthentication(session, msg.Authentication.Authentication)
	case "Bye":
		if msg.Bye == nil {
			log.Println("Received invalid bye message.", msg)
			break
		}
		pipeline = api.PipelineManager.GetPipeline(channelling.PipelineNamespaceCall, sender, session, msg.Bye.To)
		api.BusManager.Trigger(channelling.BusManagerBye, session.Id, msg.Bye.To, nil, pipeline)

		session.Unicast(msg.Bye.To, msg.Bye, pipeline)
		if pipeline != nil {
			pipeline.Close()
		}
	case "Status":
		if msg.Status == nil {
			log.Println("Received invalid status message.", msg)
			break
		}

		//log.Println("Status", msg.Status)
		session.Update(&channelling.SessionUpdate{Types: []string{"Status"}, Status: msg.Status.Status})
		session.BroadcastStatus()
	case "Chat":
		if msg.Chat == nil || msg.Chat.Chat == nil {
			log.Println("Received invalid chat message.", msg)
			break
		}

		api.HandleChat(session, msg.Chat)
	case "Conference":
		if msg.Conference == nil {
			log.Println("Received invalid conference message.", msg)
			break
		}

		api.HandleConference(session, msg.Conference)
	case "Alive":
		return msg.Alive, nil
	case "Sessions":
		if msg.Sessions == nil || msg.Sessions.Sessions == nil {
			return nil, channelling.NewDataError("bad_request", "message did not contain Sessions")
		}

		return api.HandleSessions(session, msg.Sessions.Sessions)
	case "Room":
		if msg.Room == nil {
			return nil, channelling.NewDataError("bad_request", "message did not contain Room")
		}
//.........这里部分代码省略.........